Casting sand used in a mold is reutilized sometimes by milling the mold (mold disassembly) into sand and then reclaiming the recovered sand. As the process for reclaiming recovered sand, various processes such as a wet reclaiming process, a heating reclaiming process and a dry reclaiming process have been proposed for a long time (for example, “Igata Chuzo Hou” (Mold Casting Process), 4th edition, Nov. 18, 1996, Japan Association of Casting Technology, pp. 327-330) and practically used. JP-A6-154941 discloses a process for reclaiming casting sand, which contains subjecting heat treatment to predetermined recovered sand and then subjecting the sand to dry grinding treatment.
JP-A2005-177759 discloses a dry reclaiming process which contains adding fine grains to casting sand and then reclaiming the sand.